123

 

 

 

 

123-Iodine 

is a radioactive isotope of iodine used in nuclear medicine imaging using the radiation detected by a gamma camera, which is a single photon emission computed tomography known as SPECT. The isotope's half-life is 13.2 hours and it decays by electron capture to tellurium-123 and emits gamma radiation with typical energy of 159 keV (this is the gamma primarily used for imaging). The mean percent disintegration is 83.4%.



 

Nuclear Reaction

Primary

124Xe (p,2n) 123Cs g 123Xe g 123I

Secondary

124Xe (p,pn) 123Xe g 123I



 

Conversion and Auger electrons

Energy

Frequency (>10%)

127.2 keV

13.62 %

28.4 keV / decay

 

 

Gamma and X-Ray

Energy

Frequency (>10%)

27.2 keV

27.5 keV

159.0 keV

24.65 %

45.90 %

83.30 %

172.7 keV / decay